Using Limited Purchase Specification Tests to Perform Full Linear Viscoelastic Characterization of Asphalt Binder

2010 ◽  
Vol 38 (5) ◽  
pp. 102591
Author(s):  
M. R. Mitchell ◽  
R. E. Link ◽  
B. Shane Underwood ◽  
Maryam Sadat Sakhaei Far ◽  
Y. Richard Kim
Keyword(s):  
Asphalt Binder ◽  
Specification Tests ◽  
Linear Viscoelastic

Variational characterization of real eigenvalues in linear viscoelastic oscillators

2017 ◽  
Vol 23 (10) ◽  
pp. 1377-1388 ◽  
Author(s):  
Seyyed Abbas Mohammadi ◽  
Heinrich Voss
Keyword(s):  
Degrees Of Freedom ◽  
Nonlinear Eigenvalue Problem ◽  
Eigenvalues And Eigenvectors ◽  
Variational Characterization ◽  
Viscoelastic System ◽  
New Approach ◽  
Motion Equations ◽  
Multiple Degrees Of Freedom ◽  
Linear Viscoelastic

This paper proposes a new approach for computing the real eigenvalues of a multiple-degrees-of-freedom viscoelastic system in which we assume an exponentially decaying damping. The free-motion equations lead to a nonlinear eigenvalue problem. If the system matrices are symmetric, the eigenvalues allow for a variational characterization of maxmin type, and the eigenvalues and eigenvectors can be determined very efficiently by the safeguarded iteration, which converges quadratically and, for extreme eigenvalues, monotonically. Numerical methods demonstrate the performance and the reliability of the approach. The method succeeds where some current approaches, with restrictive physical assumptions, fail.

Combined Statistical-Mechanical Characterization of a Next Generation Textured PTFE for Extreme Environments

2018 ◽  
Author(s):  
Sannmit Shinde ◽  
Ali P. Gordon ◽  
Zachary Poust ◽  
Steve Pitolaj ◽  
Jim Drago ◽  
...  
Keyword(s):  
Extreme Environments ◽  
Viscoelastic Behavior ◽  
Ceramic Particle ◽  
Operating Conditions ◽  
Operating Environments ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Statistical Mechanical ◽  
Relaxation Responses

Pressurized vessels that transfer media from one location to another often contain a bolted connection. Gaskets are essential for these systems since they confer high levels of leak mitigation across of range of operating environments (i.e., internal pressure and temperature). The balance of both sealability and compressibility must be displayed in candidate gasket materials to be subjected to aggressive operating conditions. Historically, thin gauge gasket (i.e., 1/16” thick) confer high sealability while thick gaskets offer superior compressibility (i.e., 1/8”). Fabricated with skive cut, ceramic particle-reinforced PTFE, these materials display linear viscoelastic behavior that allow consolidation to occur. For example, GYLON® 3504 is filled with Aluminosilicate Microspheres, GYLON®3510 is filled with barium sulfate, respectively, to efficiently fill crevices along the surfaces of the flange. Novel textured PTFE gasket (3504 EPX and 3510 EPX) have been developed to simultaneously confer sealability and compressibility compared to flat products. A design of experiments (DoE) approach is applied to characterize the factors that influence load relaxation responses of the both candidate textured PTFE (dual-face honeycomb) and existing (flat) gasket styles. Using an instrumented test platform analyzed. A new parameter is presented to quantify gasket efficiency. The collection of efficiency measurement methods and approach to re-torque optimization convey a novel framework that designers can invoke to facilitate improved flange performance.

scholarly journals Viscoelastic Characterization of Peripapillary Sclera: Material Properties by Quadrant in Rabbit and Monkey Eyes

2003 ◽  
Vol 125 (1) ◽  
pp. 124-131 ◽  
Author(s):  
J. Crawford Downs ◽  
J-K. Francis Suh ◽  
Kevin A. Thomas ◽  
Anthony J. Bellezza ◽  
Claude F. Burgoyne ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Viscoelastic Material ◽  
Optic Nerve Head ◽  
Material Properties ◽  
Uniaxial Stress ◽  
Species Group ◽  
Linear Viscoelastic ◽  
Viscoelastic Theory ◽  
Linear Viscoelastic Theory

In this report we characterize the viscoelastic material properties of peripapillary sclera from the four quadrants surrounding the optic nerve head in both rabbit and monkey eyes. Scleral tensile specimens harvested from each quadrant were subjected to uniaxial stress relaxation and tensile ramp to failure tests. Linear viscoelastic theory, coupled with a spectral reduced relaxation function, was employed to characterize the viscoelastic properties of the tissues. We detected no differences in the stress-strain curves of specimens from the four quadrants surrounding the optic nerve head (ONH) below a strain of 4 percent in either the rabbit or monkey. While the peripapillary sclera from monkey eyes is significantly stiffer (both instantaneously and in equilibrium) and relaxes more slowly than that from rabbits, we detected no differences in the viscoelastic material properties (tested at strains of 0–1 percent) of sclera from the four quadrants surrounding the ONH within either species group.

Multiscale Characterization of Aging and Rejuvenation in Asphalt Binder Blends with High RAP Contents

2021 ◽  
Vol 33 (10) ◽  
pp. 04021287
Author(s):  
Amal Abdelaziz ◽  
Eyad Masad ◽  
Amy Epps Martin ◽  
Edith Arámbula Mercado ◽  
Akash Bajaj
Keyword(s):  
Asphalt Binder

Application of nanotechnology in pavement engineering: a review

2020 ◽  
Vol 47 (9) ◽  
pp. 1037-1045
Author(s):  
Peerzada Mosir Shah ◽  
Mohammad Shafi Mir
Keyword(s):  
Asphalt Binder ◽  
Asphalt Mixture ◽  
Road Construction ◽  
Asphalt Pavements ◽  
Modified Asphalt Binder ◽  
Pavement Engineering ◽  
Scientists And Engineers ◽  
Primary Focus ◽  
Preparation Techniques

Nanotechnology utilizes the research and technology established at the nuclear and molecular or macromolecular levels to comprehend the nanoscale phenomena. In road construction, the bituminous materials are used in enormous amounts. The macroscopic mechanical conduct of these materials still largely relies on microstructure and physical characteristics at a micro and nano scale level. For many years, scientists and engineers have been exploring nanotechnology in civil engineering, but nanotechnology use in this sector has been limited. Nanotechnology has caught the interest of experts and has progressively penetrated into the field of pavement engineering. The article reviews the published works carried out to study the use of nanomaterials in asphalt pavements and illustrates the technique used to enhance asphalt features by the use of these nanomaterials. In this review, multiple nanomaterials are discussed followed by characterization of these nanomaterials, preparation techniques of modified asphalt binder, and finally the effect of nanomaterials on the efficiency of base asphalt binder as well as the asphalt mixture. The primary focus continues on the use of nanotechnology in pavement engineering to achieve a better atmosphere for society based on recognized pavement engineering requirements and difficulties.

scholarly journals High-Temperature Performance Evaluation of Asphaltenes-Modified Asphalt Binders

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3326
Author(s):  
Amirhossein Ghasemirad ◽  
Nura Bala ◽  
Leila Hashemian
Keyword(s):  
High Temperatures ◽  
High Performance ◽  
Asphalt Binder ◽  
Viscoelastic Behavior ◽  
Asphalt Binders ◽  
Performance Grade ◽  
Modified Binders ◽  
Linear Viscoelastic Behavior ◽  
Linear Viscoelastic ◽  
Gravity Driven

Asphalt binder comprises four main fractions—asphaltenes (A), saturates (S), aromatics (A), and resins (R)—referred to as “SARA”. Asphaltenes plays an important role in determining the linear viscoelastic behavior of asphalt binders. In this research, asphaltenes are added as a distinct modifier to improve the performance properties of asphalt binder. The modified binders are aged using a rolling thin film oven. A dynamic shear rheometer is then used to measure the rheological properties of the binders at high temperatures. Changes in the chemical composition of the modified binders are also studied through the determination of SARA fractions, using precipitation and gravity-driven chromatography methods. The rheological results show that asphaltenes improve the stiffness and elasticity of asphalt binder. It is also shown that the addition of asphaltenes raises the high Performance grade (PG) temperature of the asphalt binder, with every 6% of asphaltenes added resulting in a one-interval increase in high PG temperature grade. SARA analysis shows that the increase in polar fraction content due to the addition of asphaltenes causes the stiffness, elasticity, and viscosity of asphalt binders to increase. The results indicate that asphaltenes are an effective yet inexpensive additive to improve asphalt binder properties at high temperatures.

Characteristic Ratio and Plateau Modulus of 1,2-Polybutadiene. A Comparison with Other Rubbers

1990 ◽  
Vol 63 (5) ◽  
pp. 734-746 ◽  
Author(s):  
Jacques Roovers ◽  
Paul M. Toporowski
Keyword(s):  
Molecular Weight ◽  
Star Polymer ◽  
Dilute Solution ◽  
Plateau Modulus ◽  
Characteristic Ratio ◽  
Polymer Systems ◽  
Dilute Solution Properties ◽  
Linear Viscoelastic ◽  
Low Levels

Abstract In the course of work on linear and ring polybutadienes with 62% 1,2 units, a number of discrepancies were noted with data on polybutadienes of various microstructure available in the literature. For example, GNο=870 kPa for our 62% 1,2-polybutadiene. This is larger than GNο=730 kPa for a 56% 1,2-polybutadiene and GNο=550 kPa for a 78% 1,2-polybutadiene sample. The cis : trans ratio of our 62% 1,2-polybutadiene, prepared with potassium counterion, is 1 : 4, On the other hand, the cis : trans ratio of 62% 1,2-polybutadiene prepared with a modified Li catalyst is estimated to be 1 : 2. It is conceivable that the different cis : trans ratio leads to different properties at constant 1,2 content. Nevertheless, the low levels of both the cis and the trans units are not expected to cause more than minor differences in the properties of the polybutadienes. Correct values for GNο of model polymers are important for the study of the influence of the chemical structure on the melt characteristics of a polymer. For this reason, it was thought useful to reinvestigate 1,2-polybutadiene itself in some detail. The synthesis of narrow molecular-weight distribution 1,2-polybutadiene by anionic polymerization techniques has been described recently. The dilute-solution properties of 1,2-polybutadiene has been investigated. The melt rheology of two 1,2-polybutadiene samples have been studied, but no systematic study of the molecular-weight dependence of the melt properties was made. 1,2-Polybutadiene has been used as a component in block copolymers with 1,4-polybutadiene. These studies have permitted an investigation of the phase behavior of two rubbery blocks at room temperature. Poly(l,4-butadiene-graft-l,2-butadiene)s with well-defined composition and architecture have also been prepared. Hydrosilylated 1,2-polybutadiene has found use as the coupling agent for multiarm star polymer, and this method can easily be extended to the preparation of poly( l,2-butadiene-graft-l,4-butadiene). Hydrogenated 1,2-polybutadienes are prepared as model polymers for poly(l-butene). The synthesis and characterization of a series of 1,2-polybutadienes are described here. Special attention is given to low-molecular-weight polymers. The linear viscoelastic properties of the melts are also described. In the discussion, the relation between the characteristic ratio, C∞, and the plateau modulus, GNο, of a number of model polymer systems is explored.

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